Lecs 7-10 Flashcards
Define Community
a set of interacting species that co-occur in space and time
Define Assemblage
a set of species that co-occur in space and time
Define Functional groups
assemblage of species that either perform similar activities or work together to perform a specific ecological function
Define Guild
a set of species that co-occur in space and time and exploit the same class of resources in a similar way
Neutral Assembly Model
Communities are the result of random events of extinction and dispersal of species
-Species equivalent in all ways
Niche Assembly Model
Community is the result of interactions among species that are adapted to a particular environment
Species patterns driven by match between species traits and environment
Stochastic model vs Deterministic model
Stochastic model: Chance plays a big part in what species are present
Deterministic model: Species niches determine dynamics
Intraspecific vs Interspecific competition
Intraspecific competition: between individuals of same species
Interspecific competition: between individuals of different species
What is Competitive Exclusion
-A species outcompetes another species, causing their extinction in the community
-Important to Niche Assembly Model
PARADOX OF THE PLANKTON
Reasons why it is not a paradox:
-Not a homogeneous environment across time and space
-Species tolerance/optima more unique than taxonomy infers
-Competition not important most of the time
-Resource availability more important
Environmental Specialization
Each species has a unique set of environmental requirements
Habitat partitioning
Specializing in a specific habitat space to reduce competition with similar species
What are the different defenses against predation?
-Behavioral defenses (migration, swarming, escape)
-Morphological defenses (thick shells, long spines)
-Cyclomorphosis (seasonal morphological changes)
T/F Changes in behaviour, morphology, and life-history can be induced by environmental signals
True;
ex. change in photoperiod
Food concentration
Chemical signal from a predator (kairomones)
What is KEYSTONE PREDATOR
-A Keystone predator is a selective predator on the most competitive prey species
-Associated with increased species diversity
This is an example of:
Planktivorous fish that specialize in eating large-bodied zooplankton like Daphnia allows other zooplankton and algae species to proliferate
Keystone Predator
Level of community diversity in a lake depends on:
-Lake type
-Lake size & proximity to other lakes
-Taxonomic group
-Sampling protocol
Define Pioneer species
-species that arrive first and colonize
-typically good dispersers
Aquatic invasive species can:
-Reduce the natural biodiversity and populations of native species through:
-predation, parasitism or competition (for food or space)
-degradation or destruction of ecosystems and fish habitat
How can aquatic invasive species harm recreational activities?
damaging infrastructure
invading key recreational areas
pushing out native species from recreational fishing areas
making water unclean for swimming
How can aquatic invasive species harm native species?
parasitizing or preying upon native species, as does the sea lamprey
carrying viruses or bacteria that may cause diseases in other species
What are the impacts of zebra and quagga mussels?
-Increased water clarity via filter-feeding
-Alters N and P cycling (Nutrient shunt)
-Changes pelagic and benthic community structure
-Increases bottom-feeding fish abundance
-Reduces unionid clam abundance
What is Diel vertical migration
-Zooplankton avoid their predators through diel vertical migration
-Typical pattern is to remain in deeper, darker water during the day and rise at night to feed on the algae of the warmer epilimnion
-Effective against fish predation
What is Diel Stream Drift (DSD)
-Insect Larvae attached/below benthic substrate detach and drift downstream
-Drift occurs 10x as much at night than during the day
Autochthonous vs Allochthonous organic carbon
AUTOCHTHONOUS ORGANIC CARBON
produced within the system
algae, macrophytes
ALLOCHTHONOUS ORGANIC CARBON
produced outside the system
leaves, wood, leachate
What is Photosynthesis to Respiration (P/R) Ratio
A common measure of the trophic status of a system is the ratio of gross primary production to community respiration
If P/R ratio is >1, the system is autotrophic
If P/R ratio is <1, the system is heterotrophic
Define Secondary production
-the generation of biomass of heterotrophic (consumer) organisms in a system.
-Driven by transfer of organic material between trophic levels
Define MICROBIAL LOOP
-The microbial loop is simply a model of the pathways of carbon and nutrient cycling through microbial components of pelagic aquatic communities
-Protists and zooplankton are the most important microbial consumers and have major functions in organic carbon utilization and nutrient recycling.
